1. Field of the Invention
The present invention relates to an image-forming apparatus for recording digital images, such as a printer or copying machine, which has the function of, prior to outputting the input image data to recording paper for reproduction of the images, extracting characteristic image data from a group of plural image data, and outputting the image data from an output device to facilitate setting the conditions for forming the images.
2. Description of the Related Art
A known image-forming apparatus for reproducing (forming) a desired image on recording paper is designed so that the driving of a semiconductor laser is on/off controlled depending on image data, to irradiate a photoconductor drum as a recording medium with laser light in order to form an electrostatic latent image on the surface of the photoconductor drum which corresponds to the image data, the electrostatic latent image is then made visible by development with a toner as a coloring agent, and the developed image is transferred to a sheet of recording paper which is timely conveyed, to form an image on the sheet of recording paper which is then output outside the apparatus.
The image data may be produced by a variety of methods, including a method in which a document to be copied is read with a scanner, a method in which a personal computer or the like is used to create a graphic, text, etc. as necessary. It is well-known that apparatuses for outputting the image data from personal computers as hard copies of the images are described as "printers", while apparatuses which are integrally equipped with scanners and output data on the images captured by the scanners to record paper for reproduction of the images are referred to as "copying machines".
With prior art image-forming apparatuses for outputting the input image data to recording paper for reproduction of the images as hard copies, test copying may be performed in order to check the output state from the image-forming apparatuses in advance. For example, the image-forming apparatus disclosed in Japanese Unexamined Patent Application Disclosure HEI 6-95463 is designed so that test copying of an image to be output is performed by outputting a test copy of the image to a sheet of recording paper of size smaller than the size of the desired sheet of recording paper. This prevents wastage of recording paper, and allows the user to set (or adjust) the conditions for forming the actual image, for example, to adjust the hue of a colored image or the image density, while visually checking the test copy, in order to output an image conditioned as desired by the user.
With the image-forming apparatuses of the prior art, however, an image corresponding to the image data on the first placed document is usually formed and output as a test copy.
An operation for setting the conditions for adjustment of the densities and hues of the images is performed while visually checking the output image which is formed on the recording paper. Particularly, in cases where the image of the document is not characteristic such that it contains no areas with clear density gradations, however, not only is it impossible to set optimum density conditions by visually checking the test copy, for all the images to be formed, but also the setting operation is very troublesome and requires skills. These problems are entirely the result of test-copying the document which was selected from the plural documents only for the reason that it was first placed.
Therefore, with the image-forming apparatuses of the prior art, it is impossible to set the conditions as desired by the user for making a test copy; since a document selected only for the reason that it was first placed is reproduced on recording paper, the operation for setting the optimum conditions while visually checking the output image is troublesome. It takes therefore longer to set the conditions, and thus not only does it take a longer time to make the hard copies, but also more test copies are wasted.
In addition, in cases where the image of information to be formed extends over more than one sheet of recording paper, since a test copy is made on the first sheet only, the hard copies of the image will be made under unfavorably adjusted density conditions, with the densities of respective copies not adjusted properly.